Wireless sensor network (WSN) consists of tiny nodes with sensing, actuating, computation, wireless communications capabilities. Because of node's limited energy, the energy control Routing metric is becoming an important research topic, this paper firstly makes a summary to the existing routing metrics, accordingly analyzes that it is deficient to design routing protocols for wireless sensor networks based existing routing metric. Secondly, finds the several key characteristics of wireless sensor networks communication link. Finally, the energy control routing metric is proposed in the paper and this routing metric is adopted to improve the traditional directed diffusion routing protocol. Simulation results show that the optimization transmits power can reduce lots of power consumptions, which will meet to industrial requirements.